Inbred maize line PHAP1

ABSTRACT

An inbred maize line, designated PHAP1, the plants and seeds of inbred maize line PHAP1, methods for producing a maize plant produced by crossing the inbred line PHAP1 with itself or with another maize plant, and hybrid maize seeds and plants produced by crossing the inbred line PHAP1 with another maize line or plant.

FIELD OF THE INVENTION

This invention is in the field of maize breeding, specifically relatingto an inbred maize line designated PHAP1.

BACKGROUND OF THE INVENTION

The goal of plant breeding is to combine in a single variety or hybridvarious desirable traits. For field crops, these traits may includeresistance to diseases and insects, tolerance to heat and drought,reducing the time to crop maturity, greater yield, and better agronomicquality. With mechanical harvesting of many crops, uniformity of plantcharacteristics such as germination and stand establishment, growthrate, maturity, and plant and ear height, is important.

Field crops are bred through techniques that take advantage of theplant's method of pollination. A plant is self-pollinated if pollen fromone flower is transferred to the same or another flower of the sameplant. A plant is cross-pollinated if the pollen comes from a flower ona different plant.

Plants that have been self-pollinated and selected for type for manygenerations become homozygous at almost all gene loci and produce auniform population of true breeding progeny. A cross between twodifferent homozygous lines produces a uniform population of hybridplants that may be heterozygous for many gene loci. A cross of twoplants each heterozygous at a number of gene loci will produce apopulation of hybrid plants that differ genetically and will not beuniform.

Maize (zea mays L.), often referred to as corn in the United States, canbe bred by both self-pollination and cross-pollination techniques. Maizehas separate male and female flowers on the same plant, located on thetassel and the ear, respectively. Natural pollination occurs in maizewhen wind blows pollen from the tassels to the silks that protrude fromthe tops of the ears.

A reliable method of controlling male fertility in plants offers theopportunity for improved plant breeding. This is especially true fordevelopment of maize hybrids, which relies upon some sort of malesterility system. There are several options for controlling malefertility available to breeders, such as: manual or mechanicalemasculation (or detasseling), cytoplasmic male sterility, genetic malesterility, gametocides and the like.

Hybrid maize seed is typically produced by a male sterility systemincorporating manual or mechanical detasseling. Alternate strips of twoinbred varieties of maize are planted in a field, and the pollen-bearingtassels are removed from one of the inbreds (female). Providing thatthere is sufficient isolation from sources of foreign maize pollen, theears of the detasseled inbred will be fertilized only from the otherinbred (male), and the resulting seed is therefore hybrid and will formhybrid plants.

The laborious, and occasionally unreliable, detasseling process can beavoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMSinbred are male sterile as a result of factors resulting from thecytoplasmic, as opposed to the nuclear, genome. Thus, thischaracteristic is inherited exclusively through the female parent inmaize plants, since only the female provides cytoplasm to the fertilizedseed. CMS plants are fertilized with pollen from another inbred that isnot male-sterile. Pollen from the second inbred may or may notcontribute genes that make the hybrid plants male-fertile. Usually seedfrom detasseled fertile maize and CMS produced seed of the same hybridare blended to insure that adequate pollen loads are available forfertilization when the hybrid plants are grown.

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Theseand all patents referred to are incorporated by reference. In additionto these methods, Albertsen et al., of Pioneer Hi-Bred, U.S. patentapplication No. 07/848,433, have developed a system of nuclear malesterility which includes: identifying a gene which is critical to malefertility; silencing this native gene which is critical to malefertility; removing the native promoter from the essential malefertility gene and replacing it with an inducible promoter; insertingthis genetically engineered gene back into the plant; and thus creatinga plant that is male sterile because the inducible promoter is not "on"resulting in the male fertility gene not being transcribed. Fertility isrestored by inducing, or turning "on", the promoter, which in turnallows the gene that confers male fertility to be transcribed.

There are many other methods of conferring genetic male sterility in theart, each with its own benefits and drawbacks. These methods use avariety of approaches such as delivering into the plant a gene encodinga cytotoxic substance associated with a male tissue specific promoter oran antisense system in which a gene critical to fertility is identifiedand an antisense to that gene is inserted in the plant (see:Fabinjanski, et al. EPO 89/3010153.8 publication no. 329,308 and PCTapplication PCT/CA90/00037 published as WO 90/08828).

Another system useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, Glenn R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificity oftenlimit the usefulness of the approach.

The use of male sterile inbreds is but one factor in the production ofmaize hybrids. The development of maize hybrids requires, in general,the development of homozygous inbred lines, the crossing of these lines,and the evaluation of the crosses. Pedigree breeding and recurrentselection breeding methods are used to develop inbred lines frombreeding populations. Breeding programs combine the genetic backgroundsfrom two or more inbred lines or various other broad-based sources intobreeding pools from which new inbred lines are developed by selfing andselection of desired phenotypes. The new inbreds are crossed with otherinbred lines and the hybrids from these crosses are evaluated todetermine which of those have commercial potential.

Pedigree breeding starts with the crossing of two genotypes, each ofwhich may have one or more desirable characteristics that is lacking inthe other or which complements the other. If the two original parents donot provide all the desired characteristics, other sources can beincluded in the breeding population. In the pedigree method, superiorplants are selfed and selected in successive generations. In thesucceeding generations the heterozygous condition gives way tohomogeneous lines as a result of self-pollination and selection.Typically in the pedigree method of breeding five or more generations ofselfing and selection is practiced: F₁ →, F₂ ; F₃ →F₄ ; F₄ →F₅, etc.

Recurrent selection breeding, backcrossing for example, can be used toimprove an inbred line. Backcrossing can be used to transfer a specificdesirable trait from one inbred or source to an inbred that lacks thattrait. This can be accomplished, for example, by first crossing asuperior inbred (recurrent parent) to a donor inbred (non-recurrentparent), that carries the appropriate gene(s) for the trait in question.The progeny of this cross is then mated back to the superior recurrentparent followed by selection in the resultant progeny for the desiredtrait to be transferred from the non-recurrent parent. After five ormore backcross generations with selection for the desired trait, theprogeny will be heterozygous for loci controlling the characteristicbeing transferred, but will be like the superior parent for most oralmost all other genes. The last backcross generation is then selfed togive pure breeding progeny for the gene(s) being transferred.

A single cross hybrid maize variety is the cross of two inbred lines,each of which has a genotype that complements the genotype of the other.The hybrid progeny of the first generation is designated F₁. In thedevelopment of hybrids only the F₁ hybrid plants are sought. PreferredF₁ hybrids are more vigorous than their inbred parents. This hybridvigor, or heterosis, can be manifested in many polygenic traits,including increased vegetative growth and increased yield.

The development of a hybrid maize variety involves three steps: (1) theselection of plants from various germplasm pools for initial breedingcrosses; (2) the selfing of the selected plants from the breedingcrosses for several generations to produce a series of inbred lines,which, although different from each other, breed true and are highlyuniform; and (3) crossing the selected inbred lines with differentinbred lines to produce the hybrid progeny (F₁). During the inbreedingprocess in maize, the vigor of the lines decreases. Vigor is restoredwhen two different inbred lines are crossed to produce the hybridprogeny (F₁). An important consequence of the homozygosity andhomogeneity of the inbred lines is that the hybrid between any twoinbreds will always be the same. Once the inbreds that give a superiorhybrid have been identified, the hybrid seed can be reproducedindefinitely as long as the homogeneity of the inbred parents ismaintained.

A single cross hybrid is produced when two inbred lines are crossed toproduce the F₁ progeny. A double cross hybrid is produced from fourinbred lines crossed in pairs (A×B and C×D) and then the two F₁ hybridsare crossed again (A×B)×(C×D). Much of the hybrid vigor exhibited by F₁hybrids is lost in the next generation (F₂). Consequently, seed fromhybrid varieties is not used for planting stock.

Maize is an important and valuable field crop. Thus, a continuing goalof plant breeders is to develop high-yielding maize hybrids that areagronomically sound based on stable inbred lines. The reasons for thisgoal are obvious: to maximize the amount of grain produced with theinputs used and minimize susceptibility of the crop to environmentalstresses. To accomplish this goal, the maize breeder must select anddevelop superior inbred parental lines for producing hybrids. Thisrequires identification and selection of genetically unique individualsthat occur in a segregating population. The segregating population isthe result of a combination of crossover events plus the independentassortment of specific combinations of alleles at many gene loci thatresults in specific genotypes. Based on the number of segregating genes,the frequency of occurrence of an individual with a specific genotype isless than 1 in 10,000. Thus, even if the entire genotype of the parentshas been characterized and the desired genotype is known, only a few ifany individuals having the desired genotype may be found in a large F₂or S₀ population. Typically, however, the genotype of neither theparents nor the desired genotype is known in any detail.

In addition to the preceding problem, it is not known how the genotypewill react with the environment. This genotype by environmentinteraction is an important, yet unpredictable, factor in plantbreeding. A breeder of ordinary skill in the art cannot predict thegenotype, how that genotype will interact with various environments orthe resulting phenotypes of the developing lines, except perhaps in avery broad and general fashion. A breeder of ordinary skill in the artwould also be unable to recreate the same line twice from the very sameoriginal parents as the breeder is unable to direct how the genomescombine or how they will interact with the environmental conditions.This unpredictability results in the expenditure of large amounts ofresearch resources in the development of a superior new maize inbredline.

Pioneer research station staff propose about 400 to 500 new inbreds eachyear from over 2,000,000 pollinations. Of those proposed new inbreds,less than 50 and more commonly less than 30 are actually selected forcommercial use.

SUMMARY OF THE INVENTION

According to the invention, there is provided a novel inbred maize line,designated PHAP1. This invention thus relates to the seeds of inbredmaize line PHAP1, to the plants of inbred maize line PHAP1, and tomethods for producing a maize plant produced by crossing inbred maizeline PHAP1 with itself or another maize line. This invention furtherrelates to hybrid maize seeds and plants produced by crossing the inbredline PHAP1 with another maize line.

DEFINITIONS

In the description and examples that follow, a number of terms are usedherein. In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided. NOTE: ABS is in absolute termsand %MN is percent of the mean for the experiments in which the inbredor hybrid was grown. These designators will follow the descriptors todenote how the values are to be interpreted. Below are the descriptorsused in the data tables included herein.

ANT ROT=ANTHRACNOSE STALK ROT (Colletotrichum graminicola). A 1 to 9visual rating indicating the resistance to Anthracnose Stalk Rot. Ahigher score indicates a higher resistance.

BAR PLT=BARREN PLANTS. The percent of plants per plot that were notbarren (lack ears).

BRT STK=BRITTLE STALKS. This is a measure of the stalk breakage near thetime of pollination, and is an indication of whether a hybrid or inbredwould snap or break near the time of flowering under severe winds. Dataare presented as percentage of plants that did not snap.

BU ACR=YIELD (BUSHELS/ACRE). Yield of the grain at harvest in bushelsper acre adjusted to 15.5% moisture.

CLN=CORN LETHAL NECROSIS. Synergistic interaction of maize chloroticmottle virus (MCMV) in combination with either maize dwarf mosaic virus(MDMV-A or MDMV-B) or wheat streak mosaic virus (WSMV). A 1 to 9 visualrating indicating the resistance to Corn Lethal Necrosis. A higher scoreindicates a higher resistance.

COM RST=COMMON RUST (Puccinia sorghum. A 1 to 9 visual rating indicatingthe resistance to Common Rust. A higher score indicates a higherresistance.

DID=DRYDOWN. This represents the relative rate at which a hybrid willreach acceptable harvest moisture compared to other hybrids on a 1-9rating scale. A high score indicates a hybrid that dries relatively fastwhile a low score indicates a hybrid that dries slowly.

DIP ERS=DIPLODIA EAR MOLD SCORES (Diplodia maydis and Diplodiamacrospora). A 1 to 9 visual rating indicating the resistance toDiplodia Ear Mold. A higher score indicates a higher resistance.

DRP EAR=DROPPED EARS. A measure of the number of dropped ears per plotand represents the percentage of plants that did not drop ears prior toharvest.

D/T=DROUGHT TOLERANCE. This represents a 1-9 rating for droughttolerance, and is based on data obtained under stress conditions. A highscore indicates good drought tolerance and a low score indicates poordrought tolerance.

EAR HT=EAR HEIGHT. The ear height is a measure from the ground to thehighest placed developed ear node attachment and is measured in inches.

EAR MLD=General Ear Mold. Visual rating (1-9 score) where a "1" is verysusceptible and a "9" is very resistant. This is based on overall ratingfor ear mold of mature ears without determining the specific moldorganism, and may not be predictive for a specific ear mold.

EAR SZ=EAR SIZE. A 1 to 9 visual rating of ear size. The higher therating the larger the ear size.

ECB 1LF=EUROPEAN CORN BORER FIRST GENERATION LEAF FEEDING (Ostrinianubilalis). A 1 to 9 visual rating indicating the resistance topreflowering leaf feeding by first generation European Corn Borer. Ahigher score indicates a higher resistance.

ECB 2It=EUROPEAN CORN BORER SECOND GENERATION INCHES OF TUNNELING(Ostrinia nubilalis). Average inches of tunneling per plant in thestalk.

ECB 2SC=EUROPEAN CORN BORER SECOND GENERATION (Ostrinia nubilalis). A 1to 9 visual rating indicating post flowering degree of stalk breakageand other evidence of feeding by European Corn Borer, Second Generation.A higher score indicates a higher resistance.

ECB DPE=EUROPEAN CORN BORER DROPPED EARS (Ostrinia nubilalis). Droppedears due to European Corn Borer. Percentage of plants that did not dropears under second generation corn borer infestation.

EST CNT=EARLY STAND COUNT. This is a measure of the stand establishmentin the spring and represents the number of plants that emerge on perplot basis for the inbred or hybrid.

EYE SPT=Eye Spot (Kabatiella zeae or Aureobasidiurn zeae). A 1 to 9visual rating indicating the resistance to Eye Spot. A higher scoreindicates a higher resistance.

FUS ERS=FUSARIUM EAR ROT SCORE (Fusarium moniliforme or Fusariumsubglutinans). A 1 to 9 visual rating indicating the resistance toFusarium ear rot. A higher score indicates a higher resistance.

GDU=Growing Degree Units. Using the Barger Heat Unit Theory, whichassumes that maize growth occurs in the temperature range 50° F.-86° F.and that temperatures outside this range slow down growth; the maximumdaily heat unit accumulation is 36 and the minimum daily heat unitaccumulation is 0. The seasonal accumulation of GDU is a major factor indetermining maturity zones.

GDU SHD: GDU TO SHED. The number of growing degree units (GDUs) or heatunits required for an inbred line or hybrid to have approximately 50percent of the plants shedding pollen and is measured from the time ofplanting. Growing degree units are calculated by the Barger Method,where the heat units for a 24-hour period are: ##EQU1##

The highest maximum temperature used is 86° F. and the lowest minimumtemperature used is 50° F. For each inbred or hybrid it takes a certainnumber of GDUs to reach various stages of plant development.

GDU SLK=GDU TO SILK. The number of growing degree units required for aninbred line or hybrid to have approximately 50 percent of the plantswith silk emergence from time of planting. Growing degree units arecalculated by the Barger Method as given in GDU SHD definition.

GIB ERS=GIBBERELLA EAR ROT (PINK MOLD) (Gibberella zeae). A 1 to 9visual rating indicating the resistance to Gibberella Ear Rot. A higherscore indicates a higher resistance.

GLF SPT=Gray Leaf Spot (Cercospora zeae-maydis). A 1 to 9 visual ratingindicating the resistance to Gray Leaf Spot. A higher score indicates ahigher resistance.

GOS WLT=Goss' Wilt (Corynebacterium nebraskense). A 1 to 9 visual ratingindicating the resistance to Goss' Wilt. A higher score indicates ahigher resistance.

GRN APP=GRAIN APPEARANCE. This is a 1 to 9 rating for the generalappearance of the shelled grain as it is harvested based on such factorsas the color of harvested grain, any mold on the grain, and any crackedgrain. High scores indicate good grain quality.

H/POP=YIELD AT HIGH DENSITY. Yield ability at relatively high plantdensities on 1-9 relative rating system with a higher number indicatingthe hybrid responds well to high plant densities for yield relative toother hybrids. A 1, 5, and 9 would represent very poor, average, andvery good yield response, respectively, to increased plant density.

HC BLT=HELMINTHOSPORIUM CARBONUM LEAF BLIGHT (Helminthosporiumcarbonum). A 1 to 9 visual rating indicating the resistance toHelminthosporium infection. A higher score indicates a higherresistance.

HD SMT=HEAD SMUT (Sphacelotheca reiliana). This score indicates thepercentage of plants not infected.

INC D/A=GROSS INCOME (DOLLARS PER ACRE). Relative income per acreassuming drying costs of two cents per point above 15.5 percent harvestmoisture and current market price per bushel.

INCOME/ACRE. Income advantage of hybrid to be patented over other hybridon per acre basis.

INC ADV=GROSS INCOME ADVANTAGE. GROSS INCOME advantage of variety #1over variety #2.

L/POP=YIELD AT LOW DENSITY. Yield ability at relatively low plantdensities on a 1-9 relative system with a higher number indicating thehybrid responds well to low plant densities for yield relative to otherhybrids. A 1, 5, and 9 would represent very poor, average, and very goodyield response, respectively, to low plant density.

MDM CPX=MAIZE DWARF MOSAIC COMPLEX (MDMV=Maize Dwarf Mosaic Virus andMCDV=Maize Chlorotic Dwarf Virus). A 1 to 9 visual rating indicating theresistance to Maize Dwarf Mosaic Complex. A higher score indicates ahigher resistance.

MST=HARVEST MOISTURE. The moisture is the actual percentage moisture ofthe grain at harvest.

MST ADV=MOISTURE ADVANTAGE. The moisture advantage of variety #1 overvariety #2 as calculated by: MOISTURE of variety #2--MOISTURE of variety#1=MOISTURE ADVANTAGE of variety #1.

NLF BLT=Northern Leaf Blight (Helminthosporium turcicum or Exserohilumturcicum). A 1 to 9 visual rating indicating the resistance to NorthernLeaf Blight. A higher score indicates a higher resistance.

PLT HT=PLANT HEIGHT. This is a measure of the height of the plant fromthe ground to the tip of the tassel in inches.

POL SC=POLLEN SCORE. A 1 to 9 visual rating indicating the amount ofpollen shed. The higher the score the more pollen shed.

POL WT=POLLEN WEIGHT. This is calculated by dry weight of tasselscollected as shedding commences minus dry weight from similar tasselsharvested after shedding is complete.

It should be understood that the inbred can, through routinemanipulation of cytoplasmic or other factors, be produced in amale-sterile form. Such embodiments are also contemplated within thescope of the present claims.

POP K/A=PLANT POPULATIONS. Measured as 1000s per acre.

POP ADV=PLANT POPULATION ADVANTAGE. The plant population advantage ofvariety #1 over variety #2 as calculated by PLANT POPULATION of variety#2--PLANT POPULATION of variety #1=PLANT POPULATION ADVANTAGE of variety#1.

PRM=PREDICTED RELATIVE MATURITY. This trait, predicted relativematurity, is based on the harvest moisture of the grain. The relativematurity rating is based on a known set of checks and utilizes standardlinear regression analyses and is also referred to as the ComparativeRelative Maturity Rating System that is similar to the MinnesotaRelative Maturity Rating System.

PRM SHD=A relative measure of the growing degree units (GDU) required toreach 50% pollen shed. Relative values are predicted values from thelinear regression of observed GDU's on relative maturity of commercialchecks.

RT LDG=ROOT LODGING. Root lodging is the percentage of plants that donot root lodge; plants that lean from the vertical axis at anapproximately 30° angle or greater would be counted as root lodged.

RTL ADV=ROOT LODGING ADVANTAGE. The root lodging advantage of variety #1over variety #2.

SCT GRN=SCATTER GRAIN. A 1 to 9 visual rating indicating the amount ofscatter grain (lack of pollination or kernel abortion) on the ear. Thehigher the score the less scatter grain.

SDG VGR=SEEDLING VIGOR. This is the visual rating (1 to 9) of the amountof vegetative growth after emergence at the seedling stage(approximately five leaves). A higher score indicates better vigor.

SEL IND=SELECTION INDEX, The selection index gives a single measure ofthe hybrid's worth based on information for up to five traits. A maizebreeder may utilize his or her own set of traits for the selectionindex. One of the traits that is almost always included is yield. Theselection index data presented in the tables represent the mean valueaveraged across testing stations.

SLF BLT=SOUTHERN LEAF BLIGHT (Helminthosporium maydis or Bipolarismaydis). A 1 to 9 visual rating indicating the resistance to SouthernLeaf Blight. A higher score indicates a higher resistance.

SOU RST=SOUTHERN RUST (Puccinia polysora). A 1 to 9 visual ratingindicating the resistance to Southern Rust. A higher score indicates ahigher resistance.

STA GRN=STAY GREEN. Stay green is the measure of plant health near thetime of black layer formation (physiological maturity). A high scoreindicates better late-season plant health.

STD ADV=STALK STANDING ADVANTAGE. The advantage of variety #1 overvariety #2 for the trait STK CNT.

STK CNT=NUMBER OF PLANTS. This is the final stand or number of plantsper plot.

STK LDG=STALK LODGING. This is the percentage of plants that did notstalk lodge (stalk breakage) as measured by either natural lodging orpushing the stalks and determining the percentage of plants that breakbelow the ear.

STW WLT=Stewart's Wilt (Erwinia stewartii). A 1 to 9 visual ratingindicating the resistance to Stewart's Wilt. A higher score indicates ahigher resistance.

TAS BLS=TASSEL BLAST. A 1 to 9 visual rating was used to measure thedegree of blasting (necrosis due to heat stress) of the tassel at thetime of flowering. A 1 would indicate a very high level of blasting attime of flowering, while a 9 would have no tassel blasting.

TAS SZ=TASSEL SIZE. A 1 to 9 visual rating was used to indicate therelative size of the tassel. The higher the rating the larger thetassel.

TAS WT=TASSEL WEIGHT. This is the average weight of a tassel (grams)just prior to pollen shed.

TEX EAR=EAR TEXTURE. A 1 to 9 visual rating was used to indicate therelative hardness (smoothness of crown) of mature grain. A 1 would bevery soft (extreme dent) while a 9 would be very hard (flinty or verysmooth crown).

TILLER=TILLERS. A count of the number of tillers per plot that couldpossibly shed pollen was taken. Data is given as a percentage oftillers: number of tillers per plot divided by number of plants perplot.

TST WT=TEST WEIGHT (UNADJUSTED). The measure of the weight of the grainin pounds for a given volume (bushel).

TST WTA=TEST WEIGHT ADJUSTED. The measure of the weight of the grain inpounds for a given volume (bushel) adjusted for 15.5 percent moisture.

TSW ADV=TEST WEIGHT ADVANTAGE. The test weight advantage of variety #1over variety #2.

WIN M%=PERCENT MOISTURE WINS.

WIN Y%=PERCENT YIELD WINS.

YLD=YIELD. It is the same as BU ACR ABS.

YLD ADV=YIELD ADVANTAGE. The yield advantage of variety #1 over variety#2 as calculated by: YIELD of variety #1--YIELD variety #2=yieldadvantage of variety #1.

YLD SC=YIELD SCORE. A 1 to 9 visual rating was used to give a relativerating for yield based on plot ear piles. The higher the rating thegreater visual yield appearance.

DETAILED DESCRIPTION OF THE INVENTION

Inbred maize lines are typically developed for use in the production ofhybrid maize lines. Inbred maize lines need to be highly homogeneous,homozygous and reproducible to be useful as parents of commercialhybrids. There are many analytical methods available to determine thehomozygotic and phenotypic stability of these inbred lines.

The oldest and most traditional method of analysis is the observation ofphenotypic traits. The data is usually collected in field experimentsover the life of the maize plants to be examined. Phenotypiccharacteristics most often observed are for traits associated with plantmorphology, ear and kernel morphology, insect and disease resistance,maturity, and yield.

In addition to phenotypic observations, the genotype of a plant can alsobe examined. There are many laboratory-based techniques available forthe analysis, comparison and characterization of plant genotype; amongthese are is Isozyme Electrophoresis, Restriction Fragment LengthPolymorphisms (RFLPs), Randomly Amplified Polymorphic DNAs (RAPDs),Arbitrarily Primed Polymerase Chain Reaction (AP-PCR), DNA AmplificationFingerprinting (DAF), Sequence Characterized Amplified Regions (SCARs),Amplified Fragment Length Polymorphisms (AFLPs), and Simple SequenceRepeats (SSRs) which are also referred to as Microsatellites.

The most widely used of these laboratory techniques are IsozymeElectrophoresis and RFLPs as discussed in Lee, M., "Inbred Lines ofMaize and Their Molecular Markers," The Maize Handbook,(Springer-Verlag, New York, Inc. 1994, at 423-432) incorporated hereinby reference. Isozyme Electrophoresis is a useful tool in determininggenetic composition, although it has relatively low number of availablemarkers and the low number of allelic variants among maize inbreds.RFLPs have the advantage of revealing an exceptionally high degree ofallelic variation in maize and the number of available markers is almostlimitless.

Maize RFLP linkage maps have been rapidly constructed and widelyimplemented in genetic studies. One such study is described inBoppenmaier, et al., "Comparisons among strains of inbreds for RFLPs",Maize Genetics Cooperative Newsletter, 65:1991, pg. 90, is incorporatedherein by reference. This study used 101 RFLP markers to analyze thepatterns of 2 to 3 different deposits each of five different inbredlines. The inbred lines had been selfed from 9 to 12 times before beingadopted into 2 to 3 different breeding programs. It was results fromthese 2 to 3 different breeding programs that supplied the differentdeposits for analysis. These five lines were maintained in the separatebreeding programs by selfing or sibbing and rogueing off-type plants foran additional one to eight generations. After the RFLP analysis wascompleted, it was determined the five lines showed 0-2% residualheterozygosity. Although this was a relatively small study, it can beseen using RFLPs that the lines had been highly homozygous prior to theseparate strain maintenance.

Inbred maize line PHAP1 is a white, dent maize inbred that is bestsuited as a male in crosses for producing first generation F1 maizehybrids. Inbred maize line PHAP1 is best adapted to the North Centralregion of the United States and can be used to produce hybrids fromapproximately 112 relative maturity based on the Comparative RelativeMaturity Rating System for harvest moisture of grain. Inbred maize linePHAP1 yields well for its maturity, has good combining ability, has hardtextured ears and has a high pollen yield. Inbred maize line PHAP1 hasunique characteristic of very hard, shiny grain appearance and excellenttassel that sheds a great amount of pollen. Inbred line PHAP1 issurprising in its ability to confer very good grain quality in a whitehybrid. Inbred line PHAP1 tends to be slightly dark for grain color asan inbred per se.

The inbred has shown uniformity and stability within the limits ofenvironmental influence for all the traits as described in the VarietyDescription Information (Table 1) that follows. The inbred has beenself-pollinated and ear-rowed a sufficient number of generations withcareful attention paid to uniformity of plant type to ensure thehomozygosity and phenotypic stability necessary to use in commercialproduction. The line has been increased both by hand and in isolatedfields with continued observation for uniformity. No variant traits havebeen observed or are expected in PHAP1.

Inbred maize line PHAP1, being substantially homozygous, can bereproduced by planting seeds of the line, growing the resulting maizeplants under self-pollinating or sib-pollinating conditions withadequate isolation, and harvesting the resulting seed, using techniquesfamiliar to the agricultural arts.

                  TABLE 1                                                         ______________________________________                                        VARIETY DESCRIPTION INFORMATION                                               INBRED = PHAP1                                                                Type: Dent Region Best Adapted: North Central                                 ______________________________________                                        A.  Maturity: Average across maturity zones. Zone: 0                              GDU Shed: 1510                                                                GDU Silk: 1520                                                                No. Reps: 65                                                              B.  Plant Characteristics:                                                        Plant height (to tassel tip): 227 cm                                          Length of top ear internode: 17 cm                                            Number of ears per stalk: Single                                              Ear height (to base of top ear): 79 cm                                        Number of tillers: None                                                       Cytoplasm type: Normal                                                    C.  Leaf:                                                                         Color: (B14) Dark Green*                                                      Angle from Stalk: <30 degrees                                                 Marginal Waves: (WF9) Few                                                     Number of Leaves (mature plants): 19                                          Sheath Pubescence: (W22) Light                                                Longitudinal Creases: (OH56A) Few                                             Length (Ear node leaf): 80 cm                                                 Width (widest point, ear node leaf): 10 cm                                D.  Tassel:                                                                       Number lateral branches: 20                                                   Branch Angle from central spike: 30-40 degrees                                Pollen Shed: (KY21) Heavy based on Pollen Yield Test                          (137% of experiment means)                                                    Peduncle Length (top leaf to basal branches): 26 cm                           Anther Color: Red*                                                            Glume Color: Green*                                                       E.  Ear (Husked Ear Data Except When Stated Otherwise):                           Length: 16 cm                                                                 Weight: 113 gm                                                                Mid-point Diameter: 38 mm                                                     Silk Color: Salmon*                                                           Husk Extension (Harvest stage): Medium (Barely covering                       ear)                                                                          HuskLeaf: (>15 cm)                                                            Taper of Ear: Average                                                         Position of Shank (dry husks): Upright                                        Kernel Rows: Straight, distinct Number = 12                                   Husk Color (fresh): Light Green*                                              Husk Color (dry): Buff*                                                       Shank Length: 9 cm                                                            Shank (No. of internodes): 8                                              F.  Kernel (Dried):                                                               Size (from ear mid-point)                                                     Length: 11 mm                                                                 Width: 8 mm                                                                   Thick: 4 mm                                                                   Shape Grade (% rounds): <20 (16% medium round based on                        Parent Test Data)                                                             Pericarp Color: Colorless*                                                    Aleurone Color: Homozygous White*                                             Endosperm Color: White*                                                       Endosperm Type: Normal                                                        Gm Wt/100 Seeds (unsized): 25 gm                                          G.  Cob:                                                                          Diameter at mid-point: 23 mm                                                  Strength: Strong                                                              Color: White*                                                             H.  Diseases:                                                                     Corn Lethal Necrosis (MCMV = Maize Chlorotic Mottle                           Virus and MDMV = Maize Dwarf Mosaic Virus: Resistant                          Maize Dwarf Mosaic Complex (MDMV & MCDV = Maize                               Dwarf Virus): Susceptible                                                     Anthracnose Stalk Rot (C. graminicola): Susceptible                           S. Leaf Blight (B. maydis): Susceptible                                       Carbonum Leaf Blight (H. carbonum): Intermediate                              N. Leaf Blight (E. turcicum): Intermediate                                    Common Rust (P. sorghi): Intermediate                                         Southern Rust (P. polysora: Intermediate                                      Eye Spot (K. zeae): Intermediate                                              Gray Leaf Spot (C. zeae): Intermediate                                        Stewart's Wilt (E. stewartii): Intermediate                                   Fusarium Ear Mold (F. moniliforme): Resistant                             I.  Insects:                                                                      European Corn Borer-1 Leaf Damage (Pre-flowering):                            European Corn Borer-2 (Post-flowering):                                       The above descriptions are based on a scale of 1-9, 1 being                   highly susceptible, 9 being highly resistant.                                 S (Susceptible): Would generally represent a score of 1-3.                    I (Intermediate): Would generally represent a score of 4-5.                   R (Resistant): Would generally represent a score of 6-7.                      H (Highly Resistant): Would generally represent a score of                    8-9. Highly resistant does not imply the inbred is immune.                J.  Variety Most Closely Resembling:                                              Character Inbred                                                              Maturity PHK93                                                                Usage PHK93                                                               ______________________________________                                         *In interpreting the foregoing color designations, reference may be had t     the Munsell Glossy Book of Color, a standard color reference.                 Data for Items B, C, D, E, F, and G is based primarily on a maximum of te     reps from Johnston, Iowa grown in 1991, 1992, 1993, 1994, plus descriptio     information from the maintaining station.                                     PHK93 (PVP Certificate No. 9100094) is a Pioneer HiBred International,        Inc. proprietary inbred.                                                 

INDUSTRIAL APPLICABILITY

This invention also is directed to methods for producing a maize plantby crossing a first parent maize plant with a second parent maize plantwherein the first or second parent maize plant is an inbred maize plantof the line PHAP1. Further, both first and second parent maize plantscan come from the inbred maize line PHAP1. Thus, any such methods usingthe inbred maize line PHAP1 are part of this invention: selfing,backcrosses, hybrid production, crosses to populations, and the like.All plants produced using inbred maize line PHAP1 as a parent are withinthe scope of this invention. Advantageously, the inbred maize line isused in crosses with other, different, maize inbreds to produce firstgeneration (F₁) maize hybrid seeds and plants with superiorcharacteristics.

As used herein, the term plant includes plant cells, plant protoplasts,plant cell tissue cultures from which maize plants can be regenerated,plant calli, plant clumps, and plant cells that are intact in plants orparts of plants, such as embryos, pollen, ovules, flowers, kernels,ears, cobs, leaves, husks, stalks, roots, root tips, anthers, silk andthe like.

Duncan, Williams, Zehr, and Widholm, Planta (1985) 165:322-332 reflectsthat 97% of the plants cultured that produced callus were capable ofplant regeneration. Subsequent experiments with both inbreds and hybridsproduced 91% regenerable callus that produced plants. In a further studyin 1988, Songstad, Duncan & Widholm in Plant Cell Reports (1988),7:262-265 reports several media additions that enhance regenerability ofcallus of two inbred lines. Other published reports also indicated that"nontraditional" tissues are capable of producing somatic embryogenesisand plant regeneration. K. P. Rao, et al., Maize Genetics CooperationNewsletter, 60:64-65 (1986), refers to somatic embryogenesis from glumecallus cultures and B. V. Conger, et al., Plant Cell Reports, 6:345-347(1987) indicates somatic embryogenesis from the tissue cultures of maizeleaf segments. Thus, it is clear from the literature that the state ofthe art is such that these methods of obtaining plants are, and were,"conventional" in the sense that they are routinely used and have a veryhigh rate of success.

Tissue culture of maize is described in European Patent Application,publication 160,390, incorporated herein by reference. Maize tissueculture procedures are also described in Green and Rhodes, "PlantRegeneration in Tissue Culture of Maize," Maize for Biological Research(Plant Molecular Biology Association, Charlottesville, Va. 1982, at387-372) and in Duncan, et al., "The Production of Callus Capable ofPlant Regeneration from Immature Embryos of Numerous Zea MaysGenotypes," 165 Planta 322-332 (1985). Thus, another aspect of thisinvention is to provide cells which upon growth and differentiationproduce maize plants having the physiological and morphologicalcharacteristics of inbred line PHAP1.

Maize is used as human food, livestock feed, and as raw material inindustry. The food uses of maize, in addition to human consumption ofmaize kernels, include both products of dry- and wet-milling industries.The principal products of maize dry milling are grits, meal and flour.The maize wet-milling industry can provide maize starch, maize syrups,and dextrose for food use. Maize oil is recovered from maize germ, whichis a by-product of both dry- and wet-milling industries.

Maize, including both grain and non-grain portions of the plant, is alsoused extensively as livestock feed, primarily for beef cattle, dairycattle, hogs, and poultry.

Industrial uses of maize include production of ethanol, maize starch inthe wet-milling industry and maize flour in the dry-milling industry.The industrial applications of maize starch and flour are based onfunctional properties, such as viscosity, film formation, adhesiveproperties, and ability to suspend particles. The maize starch and flourhave application in the paper and textile industries. Other industrialuses include applications in adhesives, building materials, foundrybinders, laundry starches, explosives, oil-well muds, and other miningapplications.

Plant parts other than the grain of maize are also used in industry: forexample, stalks and husks are made into paper and wallboard and cobs areused for fuel and to make charcoal.

The seed of inbred maize line PHAP1, the plant produced from the inbredseed, the hybrid maize plant produced from the crossing of the inbred,hybrid seed, and various parts of the hybrid maize plant can be utilizedfor human food, livestock feed, and as a raw material in industry.

PERFORMANCE EXAMPLES OF PHAP1

In the examples that follow, the traits and characteristics of inbredmaize line PHAP1 are given as a line. The data collected on inbred maizeline PHAP1 is presented for the key characteristics and traits.

The inbred per se results in Table 2A compare PHAP1 to its parent,PHB72. The results show PHAP1 is significantly higher yielding with alower harvest moisture and significantly higher test weight than PHB72.Inbred maize line PHAP1 shows higher seedling vigor and early standcount than inbred maize line PHB72. Inbred PHAP1 demonstrates a lowerGDU to shed and GDU to silk than inbred PHB72. Further, PHAP1 has abetter grain appearance score compared to PHB72.

Table 2B compares the inbred per se results of PHAP1 to its otherparent, PHG47. Inbred PHAP1 is higher yielding than inbred PHG47. InbredPHAP1 has a higher harvest moisture than inbred PHG47. inbred line PHG47demonstrates a lower GDU to shed and GDU to silk than inbred PHAP1.Inbred maize line PHAP1 has superior scores for the pollen shed relatedtraits of pollen weight, pollen score and tassel size over inbred maizeline PHG47.

Table 2C compares inbred per se results of inbred maize lines PHAP1 andPHT60. Inbred PHAP1 has a higher bushel per acre yield and a higherharvest moisture than inbred PHT60. Inbred PHAP1 has a lower seedlingvigor, but a higher early stand count than inbred PHT60.

Table 2D compares inbred per se results of inbred maize lines PHAP1 andPHK93. The results show PHAP1 has higher yield, lower harvest moistureand higher test weight than PHK93. Inbred PHAP1 also has a higher earlystand count, lower GDU to shed, lower GDU to silk than inbred PHK93. Inaddition, PHAP1 has higher values for pollen score, tassel size andscatter grain than PHK93.

Table 3A results compare the general combining ability of PHAP1 andPHT60 when used in crosses with other white kernel inbreds. Inbred PHAP1confers higher yields than inbred PHT60 in hybrid combination.

Table 4A results compare the specific combining ability of inbred maizelines PHAP1 and PHT60 when crossed to inbred maize line PHW20. The PHAP1hybrid has a high bushel per acre yield and a slightly higher harvestmoisture and a higher test weight than the PHT60 hybrid. The PHAP1hybrid has higher stay green and higher grain appearance values than thePHT60 hybrid.

                                      TABLE 2A                                    __________________________________________________________________________    PAIRED INBRED COMPARISON DATA                                                 __________________________________________________________________________                BU   BU        TST  SDG  EST  TIL  GDU                                    VAR ACR  ACR  MST  WTA  VGR  CNT  LER  SHD                                    #   ABS  % MN ABS  ABS  ABS  ABS  ABS  ABS                            __________________________________________________________________________    TOTAL SUM                                                                             1   68.9 106  23.8 56.7 4.4  37.3 1.0  152.3                                  2   49.8 74   25.8 52.9 3.3  31.4 0.7  164.0                                  LOCS                                                                              15   15   16   14   26   49   34   41                                     REPS                                                                              29   29   31   27   40   103  43   48                                     DIFF                                                                              19.1 32   2.0  3.8  1.1  5.9  0.3  11.7                                   PROB                                                                              .000#                                                                              .001#                                                                              .013+                                                                              .000#                                                                              .000#                                                                              .000#                                                                              .659 .000#                          __________________________________________________________________________                GDU  POL  TAS  PLT  EAR  RT   STA  STK                                    VAR SLK  SC   SZ   HT   HT   LDG  GRN  LDG                                    #   ABS  ABS  ABS  ABS  ABS  ABS  ABS  ABS                            __________________________________________________________________________    TOTAL SUM                                                                             1   154.7                                                                              6.9  7.0  118.7                                                                              48.5 78.8 6.0  91.1                                   2   167.1                                                                              5.6  5.6  131.1                                                                              49.4 87.3 7.0  94.4                                   LOCS                                                                              41   24   23   29   29   5    21   9                                      REPS                                                                              48   27   26   37   37   9    34   16                                     DIFF                                                                              12.5 1.2  1.3  12.5 1.0  8.5  1.0  3.3                                    PROB                                                                              .000#                                                                              .000#                                                                              .000#                                                                              .008#                                                                              .796 .178 .009#                                                                              .301                           __________________________________________________________________________                BRT  GRN  SCT  EAR  TEX  EAR  BAR  DRP                                    VAR STK  APP  GRN  SZ   EAR  MLD  PLT  EAR                                    #   ABS  ABS  ABS  ABS  ABS  ABS  ABS  ABS                            __________________________________________________________________________    TOTAL SUM                                                                             1   100.0                                                                              7.2  7.3  5.8  7.5  7.7  92.1 99.0                                   2   95.2 5.7  5.4  5.8  7.3  6.8  87.2 99.5                                   LOCS                                                                              5    7    12   5    4    13   17   2                                      REPS                                                                              5    14   13   5    4    14   24   4                                      DIFF                                                                              4.8  1.5  1.9  0.0  0.3  0.8  4.9  0.5                                    PROB                                                                              .083*                                                                              .100 .001#                                                                              .000#                                                                              .638 .056*                                                                              .095*                                                                              .582                           __________________________________________________________________________                     STW   FUS   GIB  COM    ECB   ECB                                      VAR    WLT   ERS   ERS  RST    1LF   2SC                                      #      ABS   ABS   ABS  ABS    ABS   ABS                            __________________________________________________________________________    TOTAL SUM 1      5.3   7.5   9.0   5.0   7.5   7.5                                      2      7.3   8.0   9.0  7.0    6.8   7.5                                      LOCS   3     4     1    1      4     1                                        REPS   3     4     1    1      4     2                                        DIFF   2.0   0.5   0.0  2.0    0.8   0.0                                      PROB   .000# .182              .058*                                __________________________________________________________________________     VARIETY #1 = PHAP1                                                            VARIETY #2 = PHB72                                                            * = 10% SIG + = 5% SIG # = 1% SIG                                        

                                      TABLE 2B                                    __________________________________________________________________________    PAIRED INBRED COMPARISON DATA                                                 __________________________________________________________________________                BU   BU        TST  SDG  EST  TIL  GDU                                    VAR ACR  ACR  MST  WT   VGR  CNT  LER  SHD                                    #   ABS  % MN ABS  ABS  ABS  ABS  ABS  ABS                            __________________________________________________________________________    TOTAL SUM                                                                             1   67.5 101  22.6 57.7 4.3  26.5 2.2  149.4                                  2   35.4 51   17.9 58.6 4.0  24.7 1.9  136.6                                  LOCS                                                                              4    4    4    4    19   30   22   29                                     REPS                                                                              8    8    8    8    25   72   28   33                                     DIFF                                                                              32.1 50   4.7  0.9  0.3  1.8  0.3  12.8                                   PROB                                                                              .027+                                                                              .053*                                                                              .006#                                                                              .119 .249 .056*                                                                              .850 .000#                          __________________________________________________________________________                GDU  POL  POL  POL  TAS  PLT  EAR  RT                                     VAR SLK  WT   WT   SC   SZ   HT   HT   LDG                                    #   ABS  ABS  % MT ABS  ABS  ABS  ABS  ABS                            __________________________________________________________________________    TOTAL SUM                                                                             1   151.4                                                                              178.4                                                                              140  6.4  7.2  142.7                                                                              60.1 91.3                                   2   138.2                                                                              56.1 44   5.2  5.2  103.3                                                                              31.3 100.0                                  LOCS                                                                              29   1    1    15   17   18   18   1                                      REPS                                                                              33   2    2    15   18   23   23   1                                      DIFF                                                                              13.2 122.3                                                                              95   1.2  2.0  39.4 28.8 8.7                                    PROB                                                                              .000#          .039+                                                                              .000#                                                                              .009#                                                                              .006#                               __________________________________________________________________________                 STA   STK  BRT   GRN  SCT   EAR  TEX                                      VAR GRN   LDG  STK   APP  GRN   SZ   EAR                                      #   ABS   ABS  ABS   ABS  ABS   ABS  ABS                             __________________________________________________________________________    TOTAL SUM                                                                              1   5.9   88.1 100.0 6.5  7.8   5.6  7.5                                      2   2.0   96.7 100.0 8.3  6.6   3.0  5.5                                      LOCS                                                                              10    4    7     2    12    5    2                                        REPS                                                                              1 5   8    7     4    13    5    2                                        DIFF                                                                              4.0   8.6  0.0   1.8  1.3   2.6  2.0                                      PROB                                                                              .000# .186 1.00  .258 .014+ .007#                                                                              .295                            __________________________________________________________________________                     EAR    BAR   DRP  NLF  ECB   ECB                                        VAR   MLD    PLT   EAR  BLT  1LF   2SC                                        #     ABS    ABS   ABS  ABS  ABS   ABS                             __________________________________________________________________________    TOTAL SUM  1     8.0    90.8  98.8 5.0  6.5   7.5                             2          6.3   90.8   100.0 5.0  4.3  4.5                                   LOCS       11    10     1     2    4    1                                     REPS       12    15     2     2    4    2                                     DIFF       1.7   0.1    1.2   0.0  2.3  3.0                                   PROB       .011+ .990         1.00 .037+                                      __________________________________________________________________________     VARIETY #1 = PHAP1                                                            VARIETY #2 = PHB47                                                            * = 10% SIG + = 5% SIG # = 1% SIG                                        

                                      TABLE 2C                                    __________________________________________________________________________    PAIRED INBRED COMPARISON DATA                                                 __________________________________________________________________________                BU   BU        TST  SDG  EST  TIL  GDU  GDU                               VAR ACR  ACR  MST  WT   VGR  CNT  LER  SHD  SLK                               #   ABS  % MN ABS  ABS  ABS  ABS  ABS  ABS  ABS                       __________________________________________________________________________    TOTAL SUM                                                                             1   72.6 104  20.1 57.0 4.4  40.8 2.1  151.4                                                                              153.4                             2   58.0 78   18.0 58.2 5.4  38.6 0.9  144.9                                                                              149.0                             LOCS                                                                              20   20   28   16   48   96   72   93   92                                REPS                                                                              37   37   47   31   64   151  96   118  117                               DIFF                                                                              14.6 26   2.0  1.2  1.0  2.2  1.2  6.5  4.4                               PROB                                                                              .000#                                                                              .000#                                                                              .001#                                                                              .018+                                                                              .000#                                                                              .000#                                                                              .039+                                                                              .000#                                                                              .000#                     __________________________________________________________________________                POL  POL  POL  TAS  PLT  EAR  RT   STA  STK                               VAR WT   WT   SC   SZ   HT   HT   LDG  GRN  LDG                               #   ABS  % MT ABS  ABS  ABS  ABS  ABS  ABS  ABS                       __________________________________________________________________________    TOTAL SUM                                                                             1   240.9                                                                              146  6.8  7.0  102.8                                                                              42.6 42.3 6.2  92.0                              2   111.0                                                                              68   5.5  4.7  100.3                                                                              33.8 33.4 5.3  90.9                              LOCS                                                                              22   22   52   48   50   49   50   32   10                                REPS                                                                              34   34   70   54   63   62   63   46   18                                DIFF                                                                              129.9                                                                              78   1.3  2.3  2.5  8.7  8.9  0.9  1.1                               PROB                                                                              .000#                                                                              .000#                                                                              .000#                                                                              .000#                                                                              .239 .004#                                                                              .003#                                                                              .035+                                                                              .816                      __________________________________________________________________________                  BRT  GRN  SCT   EAR  TEX  EAR  BAR    DRP                                VAR  STK  APP  GRN   SZ   EAR  MLD  PLT    EAR                                #    ABS  ABS  ABS   ABS  ABS  ABS  ABS    ABS                       __________________________________________________________________________    TOTAL SUM                                                                              1    99.7 6.9  7.6   5.4  7.2  7.8  95.2   99.5                               2    96.3 6.6  7.0   4.8  7.1  6.7  93.1   100.0                              LOCS 21   8    23    16   13   24   40     4                                  REPS 25   16   25    16   13   26   47     7                                  DIFF 3.4  0.4  0.6   0.7  0.2  1.1  2.1    0.5                                PROB .003#                                                                              .378 .034+ .036+                                                                              .502 .002#                                                                              .021+  .187                      __________________________________________________________________________                     NLF  STW   FUS   GIB  COM   ECB   ECB                                   VAR   BLT  WLT   ERS   ERS  RST   1LF   2SC                                   #     ABS  ABS   ABS   ABS  ABS   ABS   ABS                        __________________________________________________________________________    TOTAL SUM  1     5.0  5.3   7.6   9.0  5.0   6.9   7.5                                   2     4.5  7.7   6.6   9.0  3.0   4.8   3.0                                   LOCS  2    3     5     1    1     9     1                                     REPS  2    3     5     1    1     9     2                                     DIFF  0.5  2.3   1.0   0.0  2.0   2.1   4.5                                   PROB  .500 .020+ .034+            .034+                            __________________________________________________________________________     VARIETY #1 = PHAP1                                                            VARIETY #2 = PHT60                                                            * = 10% SIG += 5% SIG #= 1% SIG                                          

                                      TABLE 2D                                    __________________________________________________________________________    PAIRED INBRED COMPARISON DATA                                                 __________________________________________________________________________                BU  BU       TST  SDG  EST  TIL GDU                                       VAR ACR ACR MST  WTA  VGR  CNT  LER SHD                                       #   ABS % MN                                                                              ABS  ABS  ABS  ABS  ABS ABS                               __________________________________________________________________________    TOTAL SUM                                                                             1   68.8                                                                              103 19.4 57.3 4.3  36.3 1.8 151.4                                     2   61.7                                                                              94  21.3 56.3 4.3  31.9 1.1 158.2                                     LOCS                                                                              16  16  24   14   47   79   57  78                                        REPS                                                                              29  29  39   27   61   134  67  89                                        DIFF                                                                              7.2 10  1.9  1.0  0.0  4.4  0.7 6.8                                       PROB                                                                              .116                                                                              .234                                                                              .002#                                                                              .004#                                                                              .000#                                                                              .000#                                                                              .264                                                                              .000#                             __________________________________________________________________________                  GDU  POL  TAS  PLT  EAR  RT  STA                                         VAR  SLK  SC   SZ   HT   HT   LDG GRN                                         #    ABS  ABS  ABS  ABS  ABS  ABS ABS                                __________________________________________________________________________    TOTAL SUM                                                                              1    153.7                                                                              6.9  7.0  107.0                                                                              43.1 80.9                                                                              6.1                                         2    163.1                                                                              5.9  5.6  106.1                                                                              36.4 98.5                                                                              7.4                                         LOCS 78   44   48   43   43   6   33                                          REPS 89   48   54   52   52   1 0 47                                          DIFF 9.4  1.0  1.4  1.0  6.7  17.6                                                                              1.3                                         PROB .000#                                                                              .000#                                                                              .000#                                                                              .760 .043+                                                                              .137                                                                              .000#                              __________________________________________________________________________                  STK  BRT  GRN  SCT  EAR  TEX EAR                                         VAR  LDG  STK  APP  GRN  SZ   EAR MLD                                         #    ABS  ABS  ABS  ABS  ABS  ABS ABS                                __________________________________________________________________________    TOTAL SUM                                                                              1    90.6 99.7 6.7  7.6  5.4  7.2 7.8                                         2    92.9 98.8 6.6  5.9  6.1  7.2 7.0                                         LOCS 8    15   8    23   16   13  24                                          REPS 1 5  15   1 5  25   16   1 3 26                                          DIFF 2.3  1.0  0.1  1.6  0.6  0.1 0.8                                         PROB .330 .069*                                                                              .863 .000#                                                                              .136 .753                                                                              .005#                              __________________________________________________________________________                BAR  DRP  GLF  NLF SLF                                                                              GOS STW ANT                                                                              HD                                       VAR PLT  EAR  SPT  BLT BLT                                                                              WLT WLT ROT                                                                              SMT                                      #   ABS  ABS  ABS  ABS ABS                                                                              ABS ABS ABS                                                                              ABS                              __________________________________________________________________________    TOTAL SUM                                                                             1   94.9 99.0 3.5  4.9 1.5                                                                              8.5  5.3                                                                              3.0                                                                              87.5                                     2   91.4 100.0                                                                              6.3  3.8 4.8                                                                              9.0 6.0 4.5                                                                              100.0                                    LOCS                                                                              42   2    6    5   2  1   3   2  2                                        REPS                                                                              49   4    1 1  7   4  2   3   4  4                                        DIFF                                                                              3.5  1.0  2.8  1.1 3.3                                                                              0.5 0.7 1.5                                                                              12.5                                     PROB                                                                              .030+                                                                              .085*                                                                              .004#                                                                              .011+                                                                             .314   .184                                                                              .205                                                                             .415                             __________________________________________________________________________                    MDM  FUS   GIB COM  SOU ECB  ECB                                      VAR CLN CPX  ERS   ERS RST  RST 1LF  2SC                                      #   ABS ABS  ABS   ABS ABS  ABS ABS  ABS                              __________________________________________________________________________    TOTAL SUM                                                                             1   7.0 3.0  7.2   9.0 4.4  4.5 6.6  6.3                                      2   3.0 3.0  5.2   9.0 5.7  4.0 5.1  6.8                                      LOCS                                                                              1   1    7     1   3    1   8    2                                        REPS                                                                              2   1    11    1   5    2   10   5                                        DIFF                                                                              4.0 0.0  2.0   0.0 1.2  0.5 1.5  0.5                                      PROB         .015+     .257     .064*                                                                              .500                             __________________________________________________________________________     VARIETY #1 = PHAP1                                                            VARIETY #2 = PHK93                                                            * = 10% SIG +=  5% SIG #= 1% SIG                                         

                  TABLE 3A                                                        ______________________________________                                        Average Inbred By Tester Performance Comparing PHT60                          To PHAP1 Crossed To The Same Inbred Testers And Grown                         In The Same Experiments. All Values Are Expressed As                          Percent Of The Experiment Mean Except Predicted RM,                           Selection Index, and Yield (BU/ACR)                                                         SEL    BU          EYE  ECB   ECB                               INBRED        IND    ACR    YLD  SPT  DPE   2SC                               ______________________________________                                        TOTAL   REPLIC.   138    145  145  8    3     9                               MEAN    PHT60     91     161  92   4    100   5                               WTS                                                                           MEAN    PHAP1     96     168  96   6    97    5                               WTS                                                                                   DIFF       4      6    4   1    3     0                               ______________________________________                                    

                                      TABLE 4A                                    __________________________________________________________________________    PAIRED COMPARISON DATA                                                        __________________________________________________________________________                          BU   BU        TST  SDG  EST  GDU                               VAR      PRM  ACR  ACR  MST  WT   VGR  CNT  SHD                               #   PRM  SHD  ABS  % MN % MN ABS  % MN % MN % MN                      __________________________________________________________________________    TOTAL SUM                                                                             1   108  110  157.0                                                                              94   92   58.1 67   103  100                               2   108  106  151.2                                                                              91   91   57.2 82   102  97                                LOCS                                                                              52   37   272  272  277  181  86   121  58                                REPS                                                                              52   37   314  314  320  205  103  146  72                                DIFF                                                                              0    2    5.8  4    1    0.9  15   1    3                                 PROB                                                                              .401 .000#                                                                              .000#                                                                              .000#                                                                              .026+                                                                              .000#                                                                              .000#                                                                              .083*                                                                              .000#                     __________________________________________________________________________                GDU  STK  PLT  EAR  RT   STA  STK  BRT  GRN                               VAR SLK  CNT  HT   HT   LDG  GRN  LDG  STK  APP                               #   % MN % MN % MN % MN % MN % MN % MN % MN % MN                      __________________________________________________________________________    TOTAL SUM                                                                             1    100 103  101  108  105  87   99   104  104                               2   97   104  98   101  108  74   102  98   98                                LOCS                                                                              39   336  93   92   94   110  155  44   66                                REPS                                                                              44   389  108  107  118  130  186  55   72                                DIFF                                                                              3    1    2    7    3    12   3    7    7                                 PROB                                                                              .000#                                                                              .055*                                                                              .000#                                                                              .000#                                                                              .270 .001#                                                                              .020+                                                                              .026+                                                                              .034+                     __________________________________________________________________________                DRP  GLF  NLF  SLF  ANT  HD        FUS  GIB                               VAR EAR  SPT  BLT  BLT  ROT  SMT  CLN  ERS  ERS                               #   % MN ABS  ABS  ABS  ABS  ABS  ABS  ABS  ABS                       __________________________________________________________________________    TOTAL SUM                                                                             1   100  4.0  3.3  2.5  5.2  99.0 3.5  6.7  8.0                               2   100  3.4  4.0  6.5  4.5  93.3 4.0  5.3  3.0                               LOCS                                                                              44   1 1  4    1    3    2    1    3    1                                 REPS                                                                              60   16   7    2    6    4    2    3    1                                 DIFF                                                                              0    0.6  0.8  4.0  0.7  5.7  0.5  1.3  5.0                               PROB                                                                              .158 .121 .182      .456 .361      5.47                           __________________________________________________________________________                EYE  COM  ECB  ECB  ECB  ECB                                              VAR SPT  RST  DPE  1LF  2SC  2IT                                              #   ABS  ABS  ABS  ABS  ABS  ABS                                      __________________________________________________________________________    TOTAL SUM                                                                             1   5.4  5.0  97.9 6.1  4.9  4.0                                              2   3.8  4.0  99.4 3.9  5.2  1.4                                              LOCS                                                                              8    1    9    3    23   1                                                REPS                                                                              10   1    1 1  7    28   3                                                DIFF                                                                              1.6  1.0  1.5  2.2  0.3  2.6                                              PROB                                                                              .007#     .088*                                                                              .026+                                                                              .389                                          __________________________________________________________________________     VARIETY #1 = PHW20/PHAP1                                                      VARIETY #2 = PHW20/PHT60                                                      * = 10% SIG += 5% SIG #= 1% SIG                                          

DEPOSITS

Applicant has made a deposit of at least 2500 seeds of Inbred Corn LinePHAP1 with the American Type Culture Collection (ATCC), Rockville, Md.20852 USA, ATCC Deposit No. 97390. The seeds deposited with the ATCC onDec. 26, 1995 were taken from the deposit maintained by Pioneer Hi-BredInternational, Inc., 700 Capital Square, 400 Locust Street, Des Moines,Ia. 50309-2340 since prior to the filing date of this application. Thisdeposit of the Inbred Corn Line PHAP1 will be maintained in the ATCCdepository, which is a public depository, for a period of 30 years, or 5years after the most recent request, or for the effctive life of thepatent, whichever is longer, and will be replaced if it becomesnonviable during that period. Additionally, Applicant has satisfied allthe requirements of 37 C.F.R. §§1.801-1.809, including providing anindication of the viability of the sample. Applicant imposes norestrictions on the availability of the deposited material from theATCC; however, Applicant has no authority to waive any restrictionsimposed by law on the transfer of biological material or itstransportation in commerce. Applicant does not waive any infringement ofits rights granted under this patent or under the Plant VarietyProtection Act (7USC 2321 et seq.). applicant has applied for U.S. PlantVariety Protection of PHAP1 under Application No. 9500197.

The foregoing invention has been described in detail by way ofillustration and example for purposes of clarity and understanding.However, it will be obvious that certain changes and modifications suchas single gene modifications and mutations, somoclonal variants, variantindividuals selected from large populations of the plants of the instantinbred and the like may be practiced within the scope of the invention,as limited only by the scope of the appended claims.

What is claimed is:
 1. Seed of maize inbred line designated PHAP1 andhaving ATCC Accession No.
 97390. 2. A maize plant produced by the seedof claim 1 and its plant parts.
 3. Pollen of the plant of claim
 2. 4. Anovule of the plant of claim
 2. 5. A maize plant having all thephysiological and morphological characteristics of the plant of claim 2.6. A male sterile maize plant otherwise having all the physiological andmorphological characteristics of the plant of claim
 2. 7. A tissueculture of regenerable cells of an inbred maize plant PHAP1, wherein thetissue regenerates plants capable of expressing all of the morphologicaland physiological characteristics of the maize plant named PHAP1, theseed of which have been deposited and have ATCC Accession No.
 97390. 8.A tissue culture of claim 7, the tissue culture selected from the groupconsisting of leaves, pollen, embryos, roots, root tips, anthers, silk,flowers, kernels, ears, cobs, husks, stalks, cells and protoplaststhereof.
 9. A maize plant regenerated from a tissue culture of claim 7,capable of expressing all the morphological and physiologicalcharacteristics of inbred PHAP1, the seed of which have been depositedunder ATCC Accession No.
 97390. 10. A method for producing firstgeneration (F₁) hybrid maize seed that gives rise to a hybrid maizeplant having alleles that, when expressed, contribute to hybrids thatare adapted to the north central corn belt and have a relative maturitybased on CRM of approximately 112, comprising crossing the plant ofclaim 2 with a different inbred parent maize plant and harvesting theresultant first generation (F₁) hybrid maize seed.
 11. The method ofclaim 10 wherein inbred maize plant PHAP1 is the female parent.
 12. Themethod of claim 10 wherein inbred maize plant PHAP1 is the male parent.13. An F₁ hybrid seed and plant, and its parts, grown therefrom producedby crossing an inbred maize plant according to claim 2 with another,different maize plant.